Azo dye.



doctor of philosophy,

GEORG KALISCHER, 0F FRANKFORT-ON-THE-MAIN; GERMANY, ASSIGNOR TO CASSELLA COLOR COMPANY, OF NEW YORK, N. Y.

.AZO DYE.

999,230. Specification of Letters Patent. No Drawing. Application filed December 10,v 1910. Serial No. 596,599.

To all whom it may concern:

Be it known that -I, Gnonc KALisormR,

a subject of the Kingdom of Prussia, and aresident of Wolfsgangstrasse 123, Frankforton-the-Main, Germany, have invented certain new and useful Improvements in the Manufacture of Azo Dyes, of which the following is a full description.

My invention has for its object the manufacture of new azo dyestuffs by means of the m-aminophenylnaphtimidazole.3,oxy.6.- sulfonic acid of the formula This hitherto unknown compound may be obtained by condensing with aminobenzaldehydebisulfite 1 2 diamino.3.naphthol.6.sulfonic acid. The new acid is difiicultly soluble in water, and its sodium salt crystallizes well and is somewhat difficultly soluble in cold water.

The dyestuffs prepared by combining one molecule of the new acid with one molecule of an aromatic diazo compound have a remarkable aflinity for vegetable fiber, and dye cotton directly yellow to red shades. The dyeings thus obtained may by diazotizing and developing with betanaphthol be transformed into orange to red shadesof very good fastness to washing.

If the diazotizing be carried out in substance and the diazo compound be combined with suitable azo components, dyestuffs of similar shades are obtained which possess CLOHA a good fast-ness to acids and an excellent afiinity for cotton fiber. If the last component is a compound which also introduces into the dyestufl another diazotizable aminogroup, the dyestufi's produced by means of the latter may again be diazotized and developed on the fiber, which very considerably enhances the intensity and fastness to washing. I

The process is illustrated by the followingexamples Example 1: 9.3 kilos anilin are transformed into the diazo compound which is introduced into the solution of 38 kilos m aminophenyl.1.2.naphtimidazole.3.oxy.6.- sulfonate of sodium and an excess of carbonate of soda. Coupling being complete, the who'lezis heated and salted out. The dry coloring matter is a red powder which dis solves in water with an orange-yellow color and in concentrated sulfuric acid with, a scarlet red color. It dyes cotton orange yellow shades, which on being developed with beta naphthol turn orange and become fast to washing. If the anilin is replaced by another diazo compound, dyestuffs of similar qualities are obtained, a. g. azoxyanilin (dyes orange), aminoazob'enzene sulfonic acid (dyes bluish red).

Example 2: L81 kilos of the dyestufl of Example 1 (from anilin) are finely suspended in water of about 0 C. 36 kilos hydro- Patented Aug. 1, i911.

chloric acid are first added and then grad ually 7 kilos nitrite. After stirring for severa], hours, the diazo compound is introduced into a solution of 24.6, kilos 2;6 naphtholsulfonate of soda and an excess 'of carbonate of soda. The dyestufi is isolated in.

the usual manner. It dissolves in water with an orange, and in concentrated sulfuric acid with a scarlet, color. Cotton is dyed in bright-orange shades. Such dyeings are fast to acids. If instead of the 2.6 naphtholsulfonate of soda 38 kilos m-aminophenyll- 2.naphtimidazole.5.oxy.7.sulfonate of soda be used, a dyestufi' results which dyes cotton a yellowish red shade; when developed with beta naphthol, the dyeings become more intense and completely fast to washing.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is 1. The manufacture of azo dyes by combining one molecular proportion of an aromatic compound with one molecular proportion of the m-aminophenyl.1.2.naphtimidazole.3.oxy.6.sulfonic acid, the dyestuffs thus obtained being suitable to be diazotized and s.bstancombined with an azo compound, 'tially as described.

2. The new dyestufi's of the general formula NH cnn on $3 son: a; (in which X means an aromatic radical) which in the dry state form red powders, dissolvmg in concentrated sulfuric acid with a red color and dyeing mordanted cotton in oran yellow to red shades fast to acids, substantially as described.

3. The new dyestufi? obtained by combining in alkaline solution. the diazo cornpound of'anilin with one molecular proportion of the m-aminophenyl.1.2.naphtimid- -azole.8.,oxy.6.sulfonic acid, the dyestulf thus produced being in the dry state a red powder, dissolving. in concentrated sulfonic acid with a scarlet red color dyeing" cotton ge-yelloW shades, which on being developed With beta naphthol turn orange, substantially as described.

In Witness whereof I have hereunto signed 15 iny naine this 25th day of November 1910,' in the presence of two subscribing Witnesses.

" GEORG KALIS'GHER.

Witnesses JEAN GRUND, CARL GRUND. 

